The type of embryo curvature and relative position of the radicle to the cotyledons, first utilized by de Candolle (1921a), have significantly influenced both generic and tribal delimitations to the present. By contrast, trichomes types and floral and vegetative morphology were largely neglected. Certainly, embryo type often shows considerable convergence, and many genera (e.g., Schizopetalon Sims, Lepidium Linnaeus) may have more than one type. For example, spirally coiled embryos, which are rather rare in the Brassicaceae, evolved independently in Bunias Linnaeus (Buniadeae), Erucaria Gaertner (Brassiceae), Heliophila (Heliophileae), and Schizopetalon (Schizopetaleae). Perhaps the fruits show far more convergence than any other structure in the family, especially in the type of flattening, dehiscence vs. indehiscence, development of the fruit wing, reduction is seed number, perforation or absence of septum, and development of appendages.

Although, the importance of trichome morphology in the classification of the Brassicaceae was first utilized some 118 years ago (Prantl, 1891), it was largely neglected by subsequent authors until Rollins and Banerjee (1975, 1976) showed that it holds substantial value in taxonomic work. Trichome development in Arabidopsis thaliana (e.g., Beilstein and Szymanski, 2004; Hülskamp, 2000; Schwab et al., 2000, Szymanski et al., 2000,) have determined a number of genes that control trichome development. It would be a major advancement to our knowledge of the family if such genes are sequenced across a large spectrum of the family to determine their utilities in phylogenetic studies. Here again, trichomes also exhibit homoplasy in the family, as evidenced by the presence of malpighiaceous trichomes in at least eight tribes, or the independent evolution of lepidote, webbed trichomes in the Alysseae and Physarieae.